Personal communication networks are wireless telephone systems in which a geographic area is divided into cells. Near the center of each cell is a radio antenna node coupled to a PCN node. Subscribers within range of the antenna are provided with wireless telephone service.
The PCN node contains a portion of the network intelligence, such as incoming call establishment, signal routing, and frequency assignment. Each cell is geographically defined by the shape of the radiation pattern from the cell antenna. The cells may or may not be contiguous. In some systems, known as full cellular systems, the cell coverage is continuous within a given service area, and the system permits originating or receiving calls by any subscriber within any cell, and also allows movement from cell to cell while a call is in progress. Cellular systems provide all the features of a wired telephone system, with the additional advantage of full mobility. System features, such as cell to cell mobility, require considerable complexity in each node and in the network control. For example, channel frequencies are used in more than one cell at the same time to provide adequate channel capacity. However, to avoid adjacent cell interference, the same channel frequencies are not reused in adjacent cells. If the caller leaves the cell, channel frequencies must be dynamically reassigned.
Simpler PCN systems, on the other hand, provide less than all the features of a full cellular system. For example, in some PCN system arrangements, a call can be received in any cell; however, if the subscriber leaves the cell, the call connection is lost. Still simpler PCN systems may assign a subscriber to receive or make calls from a single home cell (residential service), or permit outgoing calls only (pay phone service), or have some other mix of features and capabilities. Although PCN networks are often defined as wireless telephone networks with less than all the features of a full cellular network, the term PCN as used herein, includes all wireless telephone networks. In any event, network intelligence resides in the individual PCN nodes, and a typical PCN network might be described as a distributed intelligence network.
Numerous systems have been proposed for providing telephone service via cable television (CATV) systems, both regular (wired instrument) telephone service, and PCN. The PCN nodes are geographically distributed as before, and the CATV system provides the connection between the nodes. Communication between PCN nodes, which might have been carried by dedicated wire or otherwise, is modulated onto the cable spectrum and received point to point between PCN nodes. In this manner, the cable system acts as a preexisting wired network so that distributed intelligence PCN nodes can be deployed without adding new wiring or using dedicated telephone lines.